Fuse



1956 R. 1.. GRAUMANN ETAL 2,495,717

FUSE

Original Filed July 1, 1942 27 26 44 32 29 34 as aw 33 2 F/Q. ii

A INVENTORS RAYMOND L. GRAUMANA/ WILLIAM J DO/VAHUE, JR.

ATTORNEY Patented Jan. 31, 1950 FUSE Raymond L. Graumann; Alexandria, Va., and

- William J. Donahue, Jr., Washington, D. 0.

Original application July 1. 1942, Serial No. 449,324. Divided and this application December 27, 1946,'Serial No. 718,730

1 Claim. (Cl. 102'79) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G, 757) v This invention relates to improvements in fuzes for explosive projectiles, and the instant disclosure thereof is a division of an application for United States patent on Fuzes, filed by Raymond L. Graumann and William J. Donahue, Jr., now Patent 2,427,671, of September 23, 1947.

As brought out in that patent, a nose fuze is an explosive-loaded instrument for igniting or detonating the explosive filler of the projectile which carries it. The instant fuze, of which several forms are disclosed herein, is of the pointdetonating type. Being such it is intended ,to function by igniting the burster charge on, impact with the target.

For the purpose of classification said fuze is known as insensitive, that is to say, it is contrived particularly to function instantaneously on impact with structural members and armored parts of aircraft, or their equivalents. In comparison with this insensitiveness there is a fuze distinguished as supersensitive, which is contrived to function upon impact with the lighter and less solid parts of the same aircraft. A fuze of the latter type is disclosed in a companion divisional application for patent fo Nose fuze, filed by Raymond L. Graumann and William J. Donahue, Jr., filed December 27, 1946, Serial No. 718,729.

But regardless of the so-called insensitiveness of the instant fuze, it contains an explosive train which must be protected against premature detonation. For this reason adequate safety features are embodied in order to forestall serious accidents during thetransportation of projectiles, loading ammunition on board ships, loading projectiles into guns and, especially, while the projectile is subjected to the sudden and violent forces of being fired from the gun.

The safety features incorporated in the fuze render it both bore safe and detonator safe. That is to say, the fuze will not become armed in case the projectile encounters an obstruction in the bore of the gun, and its construction is such that should the detonator be set off prematurely the flash will not be communicated to the rest of the explosive train, consequently the explosive filler of the projectile will not be detonated.

These safety features are obtained by maintaining a break in the continuity of the explosive train of the fuze until the projectile actually begins its flight from the muzzle of the gun. Thereupon the centrifugal force developed by the spinning of the projectile becomes effective to establish the continuity of the explosive train, in other words to arm the fuze, in readiness for r 2 the firing thereof when the projectile strikes the target. a

Therefore, one of the objects of the invention is to provide a 'nose fuze which is contrived to insure the deferment of registration of the components of the explosive train with the firing pin or its equivalent until the projectile is subjected to centrifugal force such as will ordinarily be developed therein only upon firing said projectile from a gun.

A further object of the invention is to provide a fuze wherein a special feature resides in the relationship of the detonator-carrier or rotor to the body and nose'cap of the projectile.

Other objects and advantages will appear in the following specification, reference being had to the accompanying drawings in which:

Fig. 1 is a longitudinal section of a nose fuze wherein the explosive train is detonated by the shock of impact with a target;

Fig. 2 is a horizontal section of the fuze in Fig. Ltaken on the line 2-2 thereof;

Fig. 3 is a longitudinal section of a modification of the nose fuze, wherein the heavy nose or sealing disk hasan integrally attached firing pin,

I of a fuze 25. so identified in each of the forms disclosed, each of said forms comprising body 26 which has a base 2! threaded at 28 for screwing into the nose of an explosive projectile. The body 26 includes a boss 29 provided with threads 39 to which a nose cap 3| is screwed. The body 26 contains a rectilinear kerf 32 which is occupied in part by a circular detonator-carrier disk 33.

This carrier is movable by centrifugal force from an initially unarmed or safe position (Fig. 2) to an armed or firing position wherein the detonator is alined with the axis of the fuze and with the othe elements of the explosive train. Detent means is used in each form of the invention to hold the carrier in said unarmed position.

An internally threaded bore 34 in the rear of base 21 provides the mounting for a booster thimble 35. The thimble forms a backing for the kerf 32. A booster charge 33 is held in the thimble by suitable means. Communication between the booster charge and the kerf 32 is had through a lead-in 31 which, with the detonator 38 fitted in the carrier 33, completes what is referred to above as the explosive train.

3 Initially the detonator 33 is held out of registration with the lead-in 31 by the previously mentioned detent means which engage the carrier. Radially-i extending lateral bores 39, intersect the chamber 32; in an oficenter'position with reference to the carrier or rotor 33. These bores emerge at the exterior of the boss 29. The:-

detent means comprise cylindrical plugs 40 which slidably fit the bores 39. They have pin ends M which occupy recesses 42;.in..the oppositeplane faces of the rotor to prevent its turningfrom-the unarmed position. A sufficiently high degree of centrifugal force, such as is reachedionly after the projectile is fired from the muzzle ofyther gun, will displace the detents and free the rotor from turning to the armed position, it beingthe counterweights 43 (Fig. 2) whichrespond to the force to do the turning.

Springs 44 bear at their inner ends on the detent means 40 and at their outer ends against, ferrules 45'. The ferrules provide fiat bases forv the springs which are denied them by the breaking through of" the. bores 39" into the thread course. The nose cap 31 when screwed in place confines the detent' meansand' their accessories.

A chamber 4'6; in the nose cap 31! includes a. front fiat' wall" which providesacontact. ion the.- protrudin part of thecarrier 33. Thelatter is housedapproximately half and half in the, commonchamber of the boss 29, and. nose. cap 31,

wherein it. has. a .fout-noihtbearing provided by.

its perimetri'c ,contact's at the, frontflat, wall, just.

mentioned, thelateralieXtItemities. of the kerf- 32 (Fig. 2) and the. backing, afiorded by the thimble 3.5. The. chief attribute. ofthis arrange ment which. occurs, in each of the. forms, is the compactness of the. uze,, and. the. avoidance; of

having, toido fine and-expensive. machine work.v

withthe. target; theshockeimparted to; the then;

registering. detonator ignites; thalatten flashis. transmitted to theeXPIQsiyetrain, thence back. to, the explosive filler.

InFig. 3; the cylindricahhel e 5. 1 has-iamabbet" 48 deeper than the corresponding rabbet in; Figs;

The I 1 and 2, to accommodate a heavy sealing or nose disk 52. In this instance the disk has an integral firing pin 53 which fits the orifice 5|. Only the cylindrical; part of. the orificeis" used, the coni'callpartgin Figs. 1 andzbeing, omitted. The method of firing the fuze in Fig. 3 is the same as: described for Figs. 1 and 2, namely, by the shock of impact with the target.

Fig. 4 is the simplest of the three forms. The

,. nose. cap 3| terminates in a blind and blunt end 54-Whih is adapted to strike the target. When this happens the detonator 38, then in registering position, is initiated by the ensuing violent shockimpartecl. toittby the blind nose.

The invention described herein may be manufactured and used by or for the Government of theJUnitedHStatesof America for governmental purposes withouttthe payment of any royalties thereon Or therefor.

We. claim: v I

In a. fuze' a centrifugall'y;turnable detonatorcarri'er dish, a body havingarectili'near kerf out throu h. it from aback surface thereof, delineating a pair'of laterarparallel' Wall's; bYWhi:Ch' kerf" part of'the disk is. containediscrthat-the rim oi the disk contacts: the forward end-s only of'saidparallel walls with a twoepoin't contact; said dishbiein inserta'b'le: into. the kerfr; fiomsaid back surface and having the, adjacent partof its rim substantially fiush with said b9;CRlSl.l1-* -face,, ainose, cap fitted onto; the body, ha a-- chamber containing; the remaining part" the disk and having a wall'with whichthe front part ofthe rirnof the disk contacts tomake athird point contact; and a booster-carrying"thimbie fitted into the rear oiv the body into engagement Withi th back surface ofthe; body, closing the rearof' the kerf'andmroviding a: fourtlnpoi'nt contact for 'thedisk:

RAYMOND, L. GR'A-UMANN-l WI'IGLIAM J. DONAHUE; J's.

EEFERENfiES CITED her fiolloiving refierences are of record inthe. filer-oithis patent:-

, UNITED SHEA'-lli1S PATENTS Number. 1 Name Date 2,265,195,; Be riend-y .n ,Dec.. 9,, 19.41.. 2,392.,g3 .0-.= Teitscheid.. Jan. 8,..l9 i6i. 2;,4251977- Semple n Sept. 23,. 19.4.7- 2,45%;019; Nichols; ,July, 21, 19.48.-

FDREIGN'PATENTS Number Qountry Date $77,3 1:?v Italy; i Dec... 16, 1939- 516,564 Great.Britain dwn u.Jan..5,,19M) 

